dev_loss_tmo is an unsigned value. Using "%d" as output format causes
irritating negative values to be shown in sysfs.

Link: https://lore.kernel.org/r/20220902131519.16513-1-mwilck@suse.comReviewed-by: Steffen Maier <maier@linux.ibm.com>
Signed-off-by: Martin Wilck <mwilck@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>